PROCESS FOR THE PREPARATION OF AN OXIRANE, AZIRIDINE OR CYCLOPROPANE

Abstract: A process for the preparation of an oxirane, aziridine or cyclopropane of formula (I) wherein, X is oxygen, NR<4> or CHR<5>; R<1> is hydrogen, alkyl, aryl, heteroaromatic, heterocyclic or cycloalkyl; R<2> is hydrogen, alkyl, aryl, heteroaromatic, CO2R<8>, CHR<14>NHR<13>, heterocyclic or cycloalkyl; or R<1> and R<2> join together to form a cycloalkyl ring; R<3> is hydrogen, alkyl, aryl, heteroaromatic, CO2R<8>, R<8>3Sn, CONR<8>R<9> or trimethylsilyl; R<4> and R<5> are, independently, alkyl, cycloalkyl, aryl, heteroaromatic, SO2R<8>, SO3R<8>, COR<8>, CO2R<8>, CONR<8>R<9> or CN, or R<4> can also be P(O)(aryl)2; R<8> and R<9> are independently alkyl, aryl or arylalkyl; R<13> and R<14> are independently hydrogen, alkyl or aryl; the process comprising reacting a mixture of a compound of formula (II), wherein R<1>, R<2> and X are as defined above, and a sulphide of formula SR<6>R<7>, wherein R<6> and R<7> are independently alkyl, aryl or heteroaomatic, or R<6> and R<7> join together to form a cycloalkyl ring which optionally includes an additional heteroatom, with either (i) a metallocarbon obtainable by reacting an alkylmetal with a methane derivative of formula CHR<3>X'X'', wherein R<3> is as defined above, and X' and X'' are independently, a leaving group, or (ii) a metallocarbon obtainable by reacting a compound of formula (III), (wherein R<3> may not be hydrogen) with a suitable organometallic or inorganic reagent.

Description: Process for the preparation of an oxlrane, az1r1d1ne or cyclopropane The present invention relates to a process for the preparation of oxiranes from aldehydes or ketones, of aziridines from imines, or of cyclopropanes from alkenes. It is known to generate ylides from diazo compounds in the presence of rhodium (II) acetate ( .P. Doyle et al. J. Org. Chem. (1981) 465094-5102) . The use of sulphur ylides to prepare oxiranes from carbonyl compounds is well known (see, for example, B.M. Trost and L.S. Melvin "Sulphur Ylides" Academic Press, 1975). Known methods require that the reaction is carried out under basic conditions. Thus, forming oxiranes of carbonyl substrates which also contain base sensitive groups is not straightforward. Also, known methods require stoichiometric amounts of sulphide and base. According to the present invention there is provided a process for the hydrogen, alkyl or aryl; the process comprising reacting a mixture of a compound of formula (II), wherein R 1, R2 and X are as defined above, and a fi 7 fi 7 sulphide of formula SR R , wherein R and R are independently alkyl, aryl or heteroaromatic, or R and R join together to form a cycloalkyi ring which optionally includes an additional heteroatom, with either (i) a metallocarbon obtainable by reacting an alkylmetal with a methane derivative of formula CHR 3X'X", wherein R3 is as defined above, and X' and X" are independently, a leaving group, or (ii) a metallocarbon obtainable by reacting a compound of formula (III) (wherein R may not be hydrogen) with a suitable organometallic or inorganic reagent. When the compound of formula (II) is an alkene (that is when X in the c compound of formula (II) is CHR ) it is an electron deficient alkene. 1 2 When a compound of formula (II) (wherein X is 0 and neither R nor R is hydrogen (i_e it is a ketone)) is used in the process of the present invention to prepare a required oxirane of formula (I) (wherein X is 0), the reactivity of the compound of formula (II) should be balanced against the nucleophilicity of the product obtained by reacting the metallocarbon of (i) or (ii) with a sulphide of formula SR R . It is preferred that the process of the present invention is carried out in a solvent. Suitable solvents include chlorinated solvents (such as CH 2 C1 2 or CHCU), aromatic solvents (such as benzene, toluene and o-, m- or p_-xylene), aliphatic alcohols (such as methanol, ethanol or tert-butanol) . chain or cyclic ethers (such as diethyl ether, tert-butvl methyl ether, di-iso-propyl ether, glymes (for example monoglyme, diglyme or triglyme) or tetrahydrofuran) , aliphatic or alicyclic hydrocarbons (such as ri-hexane or cyclohexane) , JN.ϋ-dimethylformamide, acetonitrile or ϋ-methylpyrrolidone. The process may be carried out in a mixture of these solvents, or different reagents may be added in different solvents. It is preferred that the process of the present invention is carried out at a temperature in the range -30-100°C, especially in the range 0-50°C, such as at ambient or room temperature. The compounds of formula (I) have one, two or three chiral ring-carbon atoms and the process of the present invention is capable of forming all structural iso ers of the compounds of formula (I). Chiral values of R , 2 3 4 5 R , R , R or R can affect the stereochemical nature of the compound of formula (I) produced by the process of the present invention. The term alkyl whenever it is used refers to straight or branched alkyl chains preferably containing from 1 to 10, especially from 1 to 6, for example from 1 to 4, carbon atoms. Alkyl is, for example, methyl, ethyl , π-propyl , n-butyl or tert-butyl . Halogen is fluorine, chlorine, bromine or iodine. Alkoxy and haloalkoxy groups are straight or branched chains, preferably containing from 1 to 4 carbon atoms. Haloalkoxy and haloalkyl groups do not have a halogen that is susceptible to nucleophilic substitution. Thus, a carbon atom of a haloalkyl or haloalkoxy group must not carry a halogen atom and a hydrogen atom. Aryl includes naphthyl but is preferably phenyl . Heteroaromatic includes 5- and 6-membered aromatic rings containing one, two, three or four heteroatoms selected from the list comprising oxygen, sulphur and nitrogen and can be fused to benzenoid ring systems. Examples of heteroaromatic rings are pyridyl, pyrimidyl, pyridazinyl, pyrazinyl, triazinyl (1,2,3-, 1,2,4- and 1,3,5-), furyl, thienyl, pyrrolyl, pyrazolyl, imidazolyl, triazolyl (1,2,3- and 1,2,4-), tetrazolyl , oxazolyl , isoxazolyl, thiazolyl, isothiazolyl , quinolinyl, isoquinolinyl , cinnolinyl, quinazolinyl , quinoxalinyl, indolinyl, isoindolinyl, benzofuranyl , benzothienyl , benzimidazolyl , benzoxazole, benzthiazole, oxadiazole and thiadiazole. Heterocyclic relates to non-aromatic rings and includes include 5- and 6-membered rings containing one, two or three heteroatoms selected from the group comprising oxygen, sulphur and nitrogen. Examples are piperidine, pyrrolidine, azetidine, morpholine, tetrahydrofuran, tetrahydrothiophene, pyrroline, piperazine, isoxazoline and oxazoline. Heterocyclic rings are optionally substituted with one or more alkyl groups. The ring formed when R and R join preferably contains from 1 to 12 (for example from 2 to 10, especially from 2 to 6) carbon atoms and optionally includes an additional heteroatom (preferably a nitrogen, oxygen or sulphur atom). The ring so formed can be substituted by one or more alkyl groups or can have one or two aryl rings fused to it (see, for example, (G)). Two ring carbons may be linked together through a carbon chain (optionally containing from 1 to 6 (preferably 1, 2, 3 or 4) carbon atoms) or through a chain comprising one or more oxygen and one or more carbon atoms (for example to form a methylenedioxy group). The further ring formed may be substituted by C, , alkyl. The sulphide of formula fi 7 l-' t SR R is, for example, di ethylsulphide, diethylsulphide, (4-methoxyphenyl)methylsulphide or a sulphide of formula (A), (B), (C) , (C), (D) , (E) or (F) wherein R' and R" are, independently, hydrogen, alkyl, aryl or arylalkyl. Suitable organometallic or inorganic reagents preferably comprise * rhodium or ruthenium. Suitable reagents include Rh (0C0R ) „ , IE * * IE _. •* . Rh 2 (NR COR ) 4 or Ru 2 (0C0R ) 4 (wherein R is hydrogen, alkyl (especially methyl) or arylalkyl (such as benzyl; and R is hydrogen, alkyl (preferably methyl), C,_ 4 perfluoroalkyl (such as trifluoromethyl , 2,2,2-trifluoroethyl or pentafluoroethyl), aryl, (CHOH)alkyl or (CHOH)aryl), Rh 2 (0C0CH 3 ) 4 , Rh 2 (0C0CF 3 ) 4 , Rh 2 (NHC0CH 3 ) 4 , Rh 2 (NHC0CF 3 ) 4 , RuCl 2 (P(C 6 H 5 ) 3 ) 2 , RuCl(H 2 C 2 B g H 10 )(P(CgH 5 ) 3 ) 2 or Rh 6 (C0) lβ . Alternatively, the rhodium or ruthenium reagent can comprise the group (H) , wherein R is alkyl, aryl or arylalkyl; and p is 2 or 3. Alternatively, a suitable organometallic or inorganic reagent can comprise copper, nickel or palladium. Examples of suitable reagents include CuBr, CuCl , CuOS0 2 CF 3 , CuBr 2 , CuCl 2 , CuS0 4 , Cu(acetylacetate) 2 , [Cu(CH 3 CN) 4 ]BF 4 , Pd(0C0CH 3 ) 2 , Pd(CH 3 CN) 2 Cl 2 or Pd(C 6 H c CN) 2 Cl 2 . It is believed that a metallocarbene of formula M=CHR (wherein is, 3 for example, rhodium, ruthenium, copper, nickel or palladium, and R is as defined above but is not hydrogen) is produced by the reaction of a 3 compound of formula (III) (wherein R is not hydrogen) with a suitable organometallic or inorganic reagent. A metallocarbon obtainable by reacting an alkyl etal (such as a dialkyl zinc or a trialkyl aluminium compound) with a methane derivative of formula CHR 3 X'X" (wherein R 3 is as defined above and X' and X" are, independently, a leaving group) has a moiety that can be represented as 3 3 '-CHR L (wherein M' is a metal, such as zinc or aluminium, R is as defined above, and L is a leaving group). Such metallocarbons include zinc compounds which can be made, for example, by reacting a dialkyl zinc of 11 12 11 12 formula R R Zn [(wherein R and R are, independently, unsubstituted alkyl) and which is, for example, diethyl zinc], with a methane derivative 3 of formula CHR X'X" (wherein X' and X" are, independently, a leaving group (such as a halogen (for example chlorine, bromine or iodine), a sulphurous acid (for example mesylate or tosylate), a carboxylate or a triflate) and which is, for example, C1CHR 3 I (such as C1CH 2 I) or R 3 CHI 2 . These zinc compounds can be represented as X'-ZnCHR X" (for example I-ZnCH 9 I, I-ZnCH 2 Cl or I-Zn-CHR 3 I), Zn(CH 2 X') 2 or R n ZnCH 2 X' . Alternatively, such metallocarbons include aluminium compounds made, for example, by reacting a trialkyl aluminium of formula R R R 'Al (wherein R , R and R are, independently, unsubstituted alkyl) with a methane derivative of formula CHR X'X", wherein R , X' and X" are as defined above. These aluminium 11 12 compounds can be represented as R R A1(CH 9 X'). All alkyl groups can be substituted by one or more of aryl (such as phenyl), cycloalkyi (such as cyclopropyl) , C,_ 6 alkoxy (such as methoxy or ethoxy) , C,_ fi thioalkyl (such as ethylthio), halogen (to form, for example, CF-, or CH 2 CF 3 ), C, g haloalkoxy (such as 0CF 3 ) or C0 2 (C ι g)alkyl . In addition the alkyl groups of R or R may terminate with an aldehyde (C(H)=0) group or be interrupted with a carbonyl (C=0) group. All aryl and heteroaromatic groups can be substituted. The groups, when substituted, are preferably substituted by one or more of alkyl, haloalkyl, C, g alkoxy, halogen, C,_ 6 haloalkoxy, cycloalkyi, nitro, cyano or C0 2 (C 1 _ 6 )alkyl. Cycloalkyi rings contain, preferably from 3 to 7, especially from 3 to 6 carbon atoms. Cycloalkyi rings, can be substituted by one or more alkyl 8 8 groups, C0 2 R (wherein R is as defined above) or two ring carbons may be joined to each other by a carbon chain containing from 1 to 4 (preferably 1 or 2) carbon atoms to form a bicyclic structure. In one aspect the present invention provides a process for the preparation of an oxirane, aziridine or cyclopropane of formula (I), 4 5 1 wherein, X is oxygen, NR or CHR ; R is hydrogen, alkyl, aryl, 2 heteroaromatic, heterocyclic or cycloalkyi; R is hydrogen, alkyl, aryl, 8 1 2 heteroaromatic, C0 9 R , heterocyclic or cycloalkyi; or R and R join 3 together to form a cycloalkyi ring; R is hydrogen, alkyl, aryl, O Q Λ C heteroaromatic, C0 9 R , R ,Sn or trimethylsilyl; R and R are, 8 8 independently, alkyl, cycloalkyi, aryl, heteroaromatic, S0 2 R , S0 3 R , C0 9 R , C0NR 8 R 9 ; R 8 and R 9 are independently alkyl or aryl; the process 1 2 comprising reacting a mixture of a compound of formula (II), wherein R , R fi 7 fi and X are as defined above, and a sulphide of formula SR R , wherein R and R are independently alkyl, aryl or heteroaromatic, or R and R join together to form a cycloalkyi ring which optionally includes an additional 3 heteroatom, with either (i) a metallocarbon of formula '-CHR L, wherein L is a leaving group and * is a metal, or (ii) a metallocarbon obtainable by 3 reacting a compound of formula (III) (wherein R may not be hydrogen) with a suitable organometallic or inorganic reagent. In another aspect the present invention provides a process for the preparation of an oxirane, aziridine or cyclopropane of formula (I), wherein, X is oxygen, NR 4 or CHR5; R1 is hydrogen, alkyl, aryl, 13 2 heteroaromatic, heterocyclic, NHR or cycloalkyi; R is hydrogen, alkyl, aryl, heteroaromatic, C0 R , CHR NHR , heterocyclic or cycloalkyi; or R and R 2 join together to form a cycloalkyi ring; R3 is hydrogen, alkyl, aryl, heteroaromatic, C0 2 R 8 , R 8 3 Sn, C0NR 8 R 9 or trimethylsilyl; R 4 and R 5 form a cycloalkyi ring which optionally includes an additional heteroatom, with either (i) a metallocarbon of formula M'-CHR L, wherein L is a leaving group and M' is a metal, or (ii) a metallcarbon obtainable by reacting a 3 compound of formula (III) (wherein R may not be hydrogen) with a suitable organometallic or inorganic reagent. In a further aspect the present invention provides a process as defined above wherein R is hydrogen. In a still further aspect the present invention provides a process comprising the steps: a) reacting a metallocarbon (obtainable by reacting an alkyl metal 3 with a methane derivative of formula CHR X'X") with a sulphide of formula SR R ; and b) reacting the product of (a) with a compound of formula (II). In another aspect the present invention provides a process comprising the steps: a) reacting an alkyl metal with a methane derivative of formula CHR 3 X'X"; b) reacting the product of (a) with a sulphide of formula SR R ; and c) reacting the product of (b) with a compound of formula (II). In a further aspect the present invention provides a process comprising the steps: a) reacting a metallocarbon (obtainable by reacting a compound of 3 formula (III) (wherein R is not hydrogen) with a suitable organometallic or inorganic reagent) with a sulphide of formula SR 6 R 7 ; and, b) reacting the product of (a) with a compound of formula (II). In a still further aspect the present invention provides a process comprising the steps: 3 a) reacting a compound of formula (III) (wherein R is not hydrogen) with a suitable organometallic or inorganic reagent; b) reacting the product of (a) with a sulphide of formula SR R ; and, c) reacting the product of (b) with a compound of formula (II). In a further aspect the present invention provides a process for preparing a compound of formula (I) wherein the metallocarbon species is obtainable by reacting a compound of formula (III) (wherein R is alkyl, aryl, heteroaromatic, C0 2 R 8 , R 8 3 Sn, C0NR 8 R 9 or trimethylsilyl) with a suitable organometallic or inorganic reagent. For the process (ii) it is preferred that the nucleophilicity of the sulphide of formula SR R is such that the rate of reaction of the metallocarbon with the sulphide of formula SR R is greater than the rate of reaction of the metallocarbon with the compound of formula (III). In another aspect the present invention provides a process for preparing a compound of formula (I), wherein X, R , R , R , R and R are as defined above, the process comprising adding a compound of formula (III), wherein R is as defined above, to a mixture of a sulphide of formula SR R , wherein R and R are as defined above, a compound of 1 2 formula (II), wherein R , R and X are as defined above, and an organometallic or inorganic reagent. In a further aspect the present invention provides a process for preparing a compound of formula (I), wherein X, R , R , R , R and R are as defined above, the process comprising adding a mixture of a compound of 3 formula (III), wherein R is as defined above, and a sulphide of formula SR R , wherein R and R are as defined above, to a mixture of a compound 1 2 of formula (II), wherein R , R and X are as defined above, and an organometallic or inorganic reagent. It is possible to influence the stereochemistry of the compound of formula (I) produced by the process. This can be done by using a chiral sulphide of formula SR R (such as formulae (B) to (F)). The relative amounts of the stereochemical products will depend on the nature of the chiral sulphide used. In another aspect the present invention provides the process (ii) as previously described wherein the organometallic reagent is present in a less than stoichio etric amount (such as from 0.5 to 0.001, for example from 0.015 to 0.005, equivalents). In a further aspect the present invention provides the process (ii) as .previously described wherein a solution of the compound of formula (III) (wherein R is as defined above but is not hydrogen) is added slowly (for example over a period of 2-36, especially 5-24, hours) to a solution of a sulphide of formula SR R , a compound of formula (II) and an organometallic or inorganic reagent. By adding slowly a low concentration of the compound of formula (III) is maintained and the yield of the compound of formula (I) is increased. Under these conditions it is possible to use a less than a stoichio etric amount of sulphide (such as from 0.75 to 0.01, preferably from 0.75 to 0.1, for example from 0.5 to 0.1 (such as 0.2), equivalents). In a still further aspect the present invention provides a process as hereinbefore described wherein the compound of formula (II) is an aldehyde, imine or alkene. In another aspect the present invention provides a process as defined above wherein X is oxygen. Where it is used, it is preferred that the compound of formula (III) is purified (for example by distillation) before being used in the process of the invention. In a still further aspect the present invention provides a process for the preparation of a compound of formula (I) wherein X is as defined above 1 2 3 3 (but is preferably oxygen) and R , R and R are as defined above (but R is not hydrogen), the process comprising adding a compound of formula 3 (III), wherein R is as defined above (but not hydrogen), to a mixture of a 1 2 compound of formula (II), wherein R and R are as defined above and X is fi 7 fi 7 oxygen, a sulphide of formula SR R , wherein R and R are as defined 1 2 above, a compound of formula (II), wherein R and R are as defined above * * and X is oxygen, and a rhodium compound of formula Rh 9 (0C0R ) 4 , wherein R is as defined above (but is preferably methyl), the mixture being in the presence of a solvent. It is believed that this process proceeds as shown in Scheme 1. In another aspect the present invention provides a process for the preparation of a compound of formula (I) wherein X is as defined above 1 2 3 3 (preferably oxygen), and R , R and R are as defined above (R is especially hydrogen) the process comprising adding a compound of formula CHR X'X" to a compound of formula R R Zn preferably in a suitable solvent preferably at a temperature in the range -50 to 10°C (such as -30 to 0°C) 3 [to form a metallocarbon that can be represented as Zn-CHR X'], then adding a sulphide of formula SR R , and then adding a compound of formula (II) preferably at a temperature in the range 0 to 60°C. It is preferred that the compound of formula (II) is added some time after (for example 5-90, especially 10-60, minutes after) the sulphide of formula SR R is added. It is believed that this process proceeds as shown in Scheme 2 It is preferred that this process is carried out under anhydrous conditions. The following Examples illustrate the invention. The following abbreviations are used throughout the Examples: .p. = melting point b.p. = boiling point Ac = acetate m = multiplet s = singlet d = doublet dd = doublet of doublets ddd = doublet of doublet of doublets t = triplet dt = doublet of triplets ppm = parts per million petrol = petroleum ether boiling in the range 60-80°C Lit. 1 = C.G. Overberger et al J. Org. Chem. (1963) 28 592 Phenyl diazomethane can be prepared as described below or, alternatively, using the method described in Organic Synthesis 64207. Where necessary, apparatus, reagents or solvents were dried before use. EXAMPLE 1 N-Benzyl-p-toluene sulphona ide To a solution of benzylamine (5g, 4.67 mmol) in pyridine (25ml) was added (cautiously) p.-toluenesulphonyl chloride (lOg, 5.25 mmol). The deep red coloured solution was stirred at room temperature for 1 hour before being poured into water (80-100 ml). The oily precipitate wiiich solidified on scratching was filtered and recrystallised from ethanol to give the title compound (10.98g, 90% yield, m.p. 115-116°C, (Lit. 1 114°C)). δ H (CDC1 3 ): 7.80(2H,m); 7.25(7H,m); 4.95(lH,t); 4.05(2H,d); 2.35(3H,s)ppm. N-Nitroso-N-benzyl-p-toluenesulphonamide To a solution of N-benzyl-£-toluenesulphonamide (21g, 80 mmol) and acetic acid (100ml) in acetic anhydride (400ml) was added solid sodium nitrite (120g, 1.7 mol) in portions over a period of 12 hours at 5°C. The temperature was kept below 10°C all the time. After the addition was finished the reaction mixture was stirred at room temperature for 18 hours. The reaction mixture was poured over an excess of ice water and stirred for 1 hour. The pale yellow precipitate was filtered and washed several times with water. The crude product was recrystallized from ethanol to give the title compound as a tiny yellow needles (19.lg, 82% yield, m.p. 92-93°C, (Lit. 1 89-90°C). δ H (CDC1 3 ): 7.80(2H,m); 7.25(7H,m); 4.95(2H,s); 2.40(3H,s)ppm. Phenyldiazomethane (solution in tert-butyl methyl ether) To a solution of sodium methoxide (1.2 equivalent, 4.0ml of 1M solution in methanol) in tert-butvl methyl ether (12ml) was added M-nitroso-N-benzyl-p_-toluenesulphonamide (966mg, 3.34 mmol) in small portions at room temperature. After the addition was finished the reaction mixture was refluxed for 15-30 minutes. The reaction mixture was cooled and washed with water (3x12ml). The etheral solution of phenyldiazomethane was dried over sodium sulphate for 30 minutes. Decomposition of phenyldiazomethane with Rh^fOCOCH.,). in the presence ofu dimethylsulphide and an aldehyde The following general procedure was used for Examples 2-6. To a stirred solution of dimethylsulphide (0.5 mmol), rhodium (II) acetate (O.Olmmol) and the aldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (2 mmol in 6ml of tert-butvl methyl ether) at room temperature over a period of 24 hours. After the addition was completed the solvent was removed in vacuo and the residue was chro atographed over silica [eluent dichloromethane:petrol (2:3)]. EXAMPLE 2 traπs-Stilbene oxide Following the procedure described in Example 1 and using benzaldehyde as the aldehyde, the title oxirane was obtained in 70% yield. δ„ (CDCU): 7.35(10H,m); 3.85(2H,s)ppm. EXAMPLE 3 trans-2-(4-Nitrophenyl)-3-phenyloxirane Following the procedure described in Example 1 and using 4-nitrobenzaldehyde as the aldehyde, the title oxirane was obtained in 79% yield. δ R (CDC1 3 ): 8.30(2H,m); 7.30(7H,m); 3.95(lH,d); 3.85(lH,d)ppm. EXAMPLE 4 2-Cvclohexyl-3-phenyloxirane Following the procedure described in Example 1 and using cyclohexanecarboxaldehyde as the aldehyde, the title oxirane was obtained in 64% yield. The product was found to be a mixture of cis and trans (21:79) isomers. δ H (CDC1 3 ): 7.20(5H,m); 4.10(lH,d) (cis isomer); 3.70(lH,d) (trans isomer); 2.85 (lH,d) (cis isomer); 2.75(lH,d) (trans isomer); 2.0-0.90 (llH,m)ppm. h Q (CDC1 3 ): 138.18, 135.18(C), 128.42, 127.87, 127.91, 127.35, 126.33, 125.50, 67.43, 63.92, 57.46, 40.53, 34.92 (CH), 30.33, 29.62, 29.02, 28.10, 26.29, 25.20, 25.71, 25.56, 25.27, 25.20 (CH 2 ) . EXAMPLE 5 2-n-Butyl-3-phenyloxirane Following the procedure described in Example 1 and using valeraldehyde as the aldehyde, the title oxirane was obtained in 59% yield. The product was found to be a mixture of cis and trans (44:56) isomers. δ H (CDC1 3 ): 7.35(5H,m); 4.0(lH,d) (cis isomer); 3.55(lH,d) (trans isomer); 3.15(lH,d) (cis isomer); 2.85(lH,d) (trans isomer); 1.90-0.90(7H,m)ppm. δ Q (CDC1 3 ): 137.98, 135.82 (C) , 128.58, 128.44, 127.98, 127.43, 126.49, 125.53, 63.12, 62.85, 59.57, 58.64, 57.46 (CH) , 32.08, 28.18, 28.02, 22.55 (CH 2 ) 14.02, 13.89 (CH 3 ) . EXAMPLE 6 2-(1-Methylethyl.-3-phenyloxirane Following the procedure described in Example 1 and using iso-butvraldehvde as the aldehyde, the title oxirane was obtained in 55% yield. The product was found to be a mixture of cis and trans (40:60) isomers. δ R (CDC1 3 ): 7.35(5H,m); 4.05(lH,d) (cis isomer); 3.60(lH,d) (trans isomer); 2.85(lH,d) (cis isomer); 2.70(lH,d) (trans isomer); 1.64(lH,dd); 1.02(3H,d); 0.90(3H,d). δ ς (CDC1 3 ) : 138.05, 135.85 (C) , 128.43, 127.97, 127.38, 126.32, 125.52, 68.36, 65.18, 57.79, 57.65, 30.98, 25.87 (CH), 19.91, 19.04, 18.43, 17.91 (CH 3 ). EXAMPLE 7 2-(4-ChloroDhenv1)-3-phenv1oxiraπe To a stirred solution of a sulphide of formula (B) , wherein R' is hydrogen, (0.5mmol), rhodium (II) acetate (O.Olmmol) and 4-chloro- benzaldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butylmethyl ether, as prepared in Example 1) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica (eluent dichloromethane:petrol , 2:3) to give the trans oxirane (160mg, 70% yield and 11% ee) and the cis oxirane (30mg, 16% yield). EXAMPLE 8 Stilbene oxide Following the procedure described in Example 7, but using benzaldehyde in place of p_-chlorobenzaldehyde, trans stilbene oxide (117mg, 61% yield and 11% ee) and cis stilbene oxide (23mg, 10% yield) were obtained. EXAMPLE 9 trans-Stilbene oxide To a stirred solution of tetrahydrothiophene (O.δmmol), rhodium (II) acetate (O.Olmmol) and benzaldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butvlmethyl ether, as prepared in Example 1) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica (eluent dichloromethane:petrol , 2:3) to give the trans epoxide in 76% yield. EXAMPLE 10 trans-2-(4-Nitrophenyl)-3-phenyloxirane Following the procedure described in Example 9, but using 4-nitrobenzaldehyde in place of benzaldehyde, the title oxirane was obtained in 78% yield. EXAMPLE 11 2-(1-Methylethyl)-3-pheπyloxirane Following the procedure described in Example 9, but using iso-butvraldehvde in place of benzaldehyde, the title oxirane was obtained in 60% yield. The product was found to be a 55:45 mixture of trans:cis isomers. EXAMPLE 12 2-Cvclohexy1-3-phenv1oxirane Following the procedure described in Example 9, but using cyclohexanecarboxaldehyde in place of benzaldehyde, the title oxirane was obtained in 72% yield. The product was found to be a 80:20 mixture of trans:cis isomers. EXAMPLE 13 2-n-Butv1-3-phenyloxirane Following the procedure described in Example 9, but using valeraldehyde in place of benzaldehyde, the title oxirane was obtained in 64% yield. The product was found to be a 52:48 mixture of trans:cis isomers. EXAMPLE 14 trans-2-Methyl-2-(4-nitrophenyl)-3-phenyloxirane To a stirred solution of dimethylsulphide (73μl, lmmol), rhodium (II) acetate (4.0mg, O.Olmmol) and p-nitroacetophenone (140mg, lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butylmethyl ether, as prepared in Example 1) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica (eluent dichloromethane:petrol , 2:3) to give the trans epoxide (143mg, 56% yield) as a white solid m.p. 93-94°C. δ H (CDC1 3 ): 8.01(2H,m); 7.4(2H,m); 7.01(5H,m); 4.25(lH,s); 1.8(3H,s) ppm. EXAMPLE 15 2-(Ethyl cvcloprop-l-yl-2-carboxy ate)-3-phenyloxirane Using ethyl 2-formyl-l-cyclopropanecarboxylate, the title epoxide was obtained in 72% yield following the same procedure described in Example 9. The product was found to be a 50:50 mixture of cis:trans isomers on the epoxide ring. δ H (CDC1 3 ): 7.25(5H,m); 3.75(lH,d); 3.6(lH,d); 2.95(lH,dd); 2.8(lH,dd); 1.75(2H,m); 1.25(5H,m) ppm. EXAMPLE 16 Phenyldiazomethane (solution in diethyl ether) To a solution of sodium methoxide (600μl of 1M solution in methanol) in diethyl ether (6ml) was added fi-nitroso-.N-benzyl-p_-toluenesulphonamide (483mg, 1.67mmol, prepared as in Example 1), in small portions at room temperature. After the addition was finished the reaction mixture was refluxed for 15-30 minutes. The reaction mixture was cooled and washed with water (3x6ml). The etheral solution of phenyldiazomethane (lmmol) was dried over sodium sulphate for 30 minutes. Decomposition of phenyldiazomethane with Rh^fOCOCH-,). in the presence of di ethylsulphide and an aldehyde The following general procedure was used for Examples 17-21. To a stirred solution of dimethylsulphide (1 mmol), rhodium (II) acetate (O.Olmmol) and the aldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (1 mmol in 6ml of diethyl ether) at room temperature over a period of 3 hours. After the addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica [eluent dichloromethane:petrol (2:3)]. EXAMPLE 17 trans-Stilbene oxide Following the procedure described in Example 16 and using benzaldehyde as the aldehyde, the title oxirane was obtained in 70% yield. EXAMPLE 18 trans-2-(4-Nitrophenyl)-3-phenyloxirane Following the procedure described in Example 16 and using 4-nitrobenzaldehyde as the aldehyde, the title oxirane was obtained in 62% yield. EXAMPLE 19 2-Cvclohexyl-3-phenyloxirane Following the procedure described in Example 16 and using cyclohexanecarboxaldehyde as the aldehyde, the title oxirane was obtained in 66% yield. The product was found to be a mixture of cis and trans (21:79) isomers. EXAMPLE 20 2-n-Butyl-3-phenyloxirane Following the procedure described in Example 16 and using valeraldehyde as the aldehyde, the title oxirane was obtained in 55% yield. The product was found to be a mixture of cis and trans (44:56) isomers. EXAMPLE 21 2-(l-Methylethyl)-3-phenyloxirane Following the procedure described in Example 16 ana using iso-butyraldehyde as the aldehyde, the title oxirane was obtained in 64% yield. The product was found to be a mixture of cis and trans (40:60) isomers. EXAMPLE 22 Ethyl (3-phenyloxiran-2-yl)cvc1oprop-2-v1)carboxylate Following the procedure described in Example 9, but using ethyl 2-formyl-l-cyclopropanecarboxylate in place of benzaldehyde, the title oxirane was obtained in 72% yield. The product was found to be a 50:50 mixture of trans:cis isomers. δ., (CDC ): 7.25(5H,m); 3.75(lH,d,J=2 Hz) (cis isomer); 3.6(lH,d,J=2 Hz)(trans isomer); 2.95(lH,dd,J=2 Hz,J=3.5 Hz) (cis isomer); 2.8(lH,dd,J=2.0 Hz,J=4.5 Hz) (trans isomer); 1.75 (m,2H); 1.25(5H,m)ppm. EXAMPLE 23 2-(4-Acetyloxyphenyl)-3-phenyloxirane Following the procedure described in Example 9, but using 4-acetoxybenzaldehyde in place of benzaldehyde, the title oxirane was obtained in 20% yield. δ H (CDC1 3 ): 7.10-7.45(9H,m); 3.85(lH,d,J=2 Hz); 2.80(lH,d,J=2.0 Hz); 2.25(3H,s)ppm. EXAMPLE 24 Styrene oxide To a solution of diethyl zinc (1.8ml of 1.1M solution in toluene, 2.0mmol) in 1,2-dichloroethane (6ml) was added chloroiododomethane (218μl. 3mmol) at -15°C and the reaction mixture was stirred for 15 minutes. Tetrahydrothiophene (240μl , 3mmol) and benzaldehyde (lmmol) were added and the reaction mixture was warmed to room temperature. After stirring at that temperature for 1 hour the reaction mixture was refluxed for one hour. After cooling to room temperature, the reaction mixture was diluted with dichloromethane (20ml) and washed with saturated solution of NH-C1 (3x5ml). The organic layer was dried over MgS0 4 . After filtration of the drying agent the solvent was removed in vacuo and the residue was chromatographed over silica (eluant petrol :dichloromethane (40:60) to give the title compound as a clear oil (92%). EXAMPLE 25 p-Nitrostyrene oxide Following the procedure described in Example 24, but using P_-nitrobenzaldehyde in place of benzaldehyde, the title oxirane was produced in 95% yield. EXAMPLE 26 4-Chlorostyrene oxide Following the procedure described in Example 24, but using 4-chlorobenzaldehyde in place of benzaldehyde, the title oxirane was produced in 65% yield. EXAMPLE 27 Cvclohexylethylene oxide Following the procedure described in Example 24, but using cyclohexane carboxaldehyde in place of benzaldehyde, the title oxirane was produced in 60% yield. EXAMPLE 28 2-(4-Chlorophenyl)-3-phenyloxirane To a stirred solution of tetrahydrothiophene (0.lmmol), rhodium (II) acetate (O.Olmmol) and p-chlorobenzaldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butylmethyl ether) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica to provide the title oxirane in 26% yield. EXAMPLE 29 2-(4-Chlorophenyl)-3-phenyloxirane To a stirred solution of dimethyl sulphide (0.lmmol), rhodium (II) acetate (O.Olmmol) and p-chlorobenzaldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butylmethyl ether) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica to provide the title oxirane in 46% yield. EXAMPLE 30 2-(4-Chlorophenyl)-3-phenyloxirane To a stirred solution of dimethyl sulphide (0.25mmol), rhodium (II) acetate (O.Olmmol) and p-chlorobenzaldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butylmethyl ether) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica to provide the title oxirane in 76% yield. EXAMPLE 31 2-(4-Chlorophenyl)-3-phenyloxirane To a stirred solution of dimethyl sulphide (0.20mmol), rhodium (II) acetate (O.Olmmol) and p-chlorobenzaldehyde (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butylmethyl ether) at room temperature over a period of 24 hours. After addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica to provide the title oxirane in 76% yield. EXAMPLE 32 Stilbene oxide Following the procedure described in Example 31, but using benzaldehyde in place of p-chlorobenzeldehyde, the title oxirane was produced in 74% yield. EXAMPLE 33 2-Cvclohexyl-3-phenyloxirane Following the procedure described in Example 31, but using cyclohexane carboxaldehyde in place of p-chlorobenzeldehyde, the title oxirane was produced in 51% yield. EXAMPLE 34 2-n-Butyl-3-phenv1oxirane Following the procedure described in Example 31, but using valeraldehyde in place of p-chlorobenzeldehyde, the title oxirane was produced in 45% yield. EXAMPLE 35 2-(4-Nitrophenyl)-3-phenyloxirane Following the procedure described in Example 31, but using p-nitrobenzaldehyde in place of p-chlorobenzeldehyde, the title oxirane was produced in 89% yield. EXAMPLE 36 Phenyl diazomethane N-Nitroso-N-benzyl-β-toluene sulphonamide (966mg, 3.33mmol) was added in small portions to a solution of sodium methoxide (2.0ml of 2M solution in ethanol) in t-butyl methyl ether (12ml) and methanol (2ml) at room temperature. After the addition was finished the reaction mixture was •refluxed for 15-30 min. The reaction mixture was cooled and washed with water (3x6ml). The ethereal solution of phenyl diazomethane was dried over sodium sulphate for 30 minutes. The solvent was removed in vacuo and the residue distilled under reduce pressure to give phenyl diazomethane as a dark red oil (30% yield, b.p. 20°C at 1 mmHg) which was immediately dissolved in i-butyl methyl ether (6ml). General method for epoxidation using phenyl diazomethane. an aldehyde and Rh„(0Ac) in the presence of dimethyl sulfide Phenyl diazomethane (lmmol in 6ml of t-butyl methyl ether) was added to a stirred solution of dimethyl sulfide (0.2mmol), rhodium (II) acetate (4.0mg, O.Olmmol) and an aldehyde (lmmol) in dichloromethane (4ml) at room temperature over a period of 24 hours. After the addition was complete the solvent was removed in vacuo and the residue was chromatographed using silica [eluent dichloromethane:petrol (2:3)]. EXAMPLE 37 Stilbene oxide Using the method of Example 36 with benzaldehyde gave the title compound in 74% yield as a mixture of cis and trans (12:88) isomers. EXAMPLE 38 trans-2-(4-Nitrophenyl)-3-pheπyloxirane Using the method of Example 36 with 4-nitrobenzaldehyde gave the title compound in 89% yield as a yellow solid m.p. 126-128°C. EXAMPLE 39 2-(4-Chlorophenv1)-3-phenyloxirane Using the method of Example 36 with 4-chlorobenzaldehyde gave the title compound in 76% yield as a white solid and as a mixture of cis and trans (20:80) isomers. EXAMPLE 40 2-Cvclohexyl-3-phenyloxirane Using the method of Example 36 with cyclohexane carboxaldehyde gave the title compound in 51% yield as a clear oil and as a mixture of cis and trans (21:79) isomers. EXAMPLE 41 2-n-Butyl-3-phenyloxirane Using the method of Example 36 with valeraldehyde gave the title compound in 45% yield as a clear oil and as a mixture of cis and trans (44:56) isomers. EXAMPLE 42 2.2-Dimethyl -4- (3-phenyl oxi ran-2-yl ) -1 .3-dihvdrodioxol e Using the method of Example 36 with 2,2-dimethyl-4-formyl-l,3 -dihydrodioxole but using lmmol of dimethyl sulfide gave the title compound in 73% yield as a clear oil and as a mixture of diastereomers. δ H (CDC1 3 ,400 MHz): 7.4-7.2(5H,m) , 4.3-3.90(4.4H,m) , 3.87(0.33H,d,J=2.0Hz) , 3.83(0.34H,d,J=2.0Hz) , 3.62-3.56(0.33H, ddd,J=9.0Hz,J=6.0Hz,J=5.0Hz) , 3.30(0.33H,dd, J=4.0Hz, - 9.0Hz), 3.15-3.10(0.67H,two dd, J=2.0Hz, J=6.0Hz), 1.30 and 1.25 (6H,s) ppm. EXAMPLE 43 Ethyl 2.3-eDθxy-3-phenv1 oropionate Using the method of Example 36 with ethyl glyoxylate but using lmmol of dimethyl sulfide gave the title compound in 53% yield as a clear oil. δ H (CDCl 3 , 250 MHz): 7.4-7.2(5H,m) , 4.36-4.20 (2H,m), 4.10 (lH,d,J=2.0 Hz), 3.51 (lH,d,J=2.0Hz), 1.50(3H,t,J=8Hz)ppm. EXAMPLE 44 1.3-Diphenyl-2.3-epoxypropane Using the method of Example 36 with phenylacetaldehyde but using (lmmol) of dimethyl sulfide gave the title compound in 80% yield as a clear oil. δ H (CDC1 3 , 250 MHz): 7.3-7.1 (lOH.m), 3.55 (lH,d,J=2.0 Hz), 3.05 (IH, dt,J=6.0 Hz,J=2.0 Hz), 2.80 (2H,d,J=6.0 Hz)ppm. EXAMPLE 45 Stilbene oxide Phenyl diazomethane (lmmol in 6 ml of 1>butylmethylether) was added to a stirred solution of a sulphide of formula (B) wherein R' is hydrogen (0.2mmol), rhodium (II) acetate (4.0mg, O.Olmmol) and benzaldehyde (lmmol) in dichloromethane (4ml) at room temperature over a period of 24 hours. After the addition was complete the solvent was removed in vacuo and the residue was chromatographed over silica [eluent dichloromethane: petrol (2:3)] to give the titled compound in 58% yield and 11% ee. EXAMPLE 46 2-(4-Chloropheπyl)-3-phenyloxirane Using the method of Example 45 with 4-chlorobenzaldehyde in place of benzaldehyde gave the title compound in 62% yield and 12% ee as a white solid. This was a mixture of cis and trans (16:84) isomers. EXAMPLE 47 1-Benzoyl-2.3-diphenylcyclopropane Phenyl diazomethane (prepared as in Example 36, O.δmmol in 3ml of i-butyl methyl ether) was added to a stirred solution of dimethylsulphide (7.3ml; 0.lmmol), rhodium (II) acetate (2mg; O.OOδmmol) and chalcone (103mg; O.δmmol) in dichloromethane (2ml) at room temperature over a period of 24 hours. After the addition was complete the solvent was removed in vacuo and the residue was chromatographed over silica [eluent dichloromethane:petrol (2:3)], to give the title compound as a 4:1 mixture of trans:cis cyclopropanes as a yellowy solid (58mg; 39%). δ R (CDC1 3 ,250 MHz); 3.27(0.8H,dd,J=6.5 and 9 Hz), 3.32(0.4H,d,J=5 Hz), 3.38(0.8H,dd,J=5.5 and 9.5 Hz), 3.54(0.2H,t,J=5 Hz), 3.62(0.8H,dd,J=5.5 and 6.5 Hz), 7-7.5(13H,m), 7.95(1.6H,m) , 8.15(0.4H,m)ppm. The same method was applied for the cyclopropanation of chalcone using a stoichiometric amount of dimethyl sulphide (36.5μl; O.δmmol). Column chromatography over silica afforded the title compound as a 5:1 mixture of trans; cis cyclopropanes as a yellowy solid (54mg; 36.2%). EXAMPLE 48 Stilbene oxide A solution of phenyldiazomethane (lmmol in 6ml of t>butyl methyl ether) was added, over a period of 12 hours, to a solution of a sulphide of formula (C) wherein R 1 and R" are both hydrogen (for preparation see J. Org. Chem. 44 (20) 3δ98-9 (1979); 198mg, l.Ommol), rhodium (II) acetate (4mg, O.Olmmol) and benzaldehyde (190μl, l.Ommol) in dichloromethane (4ml). Upon completion of the addition, the solvent was removed in vacuo and the residue chromatographed using silica gel eluting with dichloro¬ methane:petrol 40:60 to yield trans-2,3-diphenyl oxirane (31mg, 16%, δl%ee) and cis-2,3-diphenyl oxirane (3mg, 1.5%). EXAMPLE 49 trans-Stilbene oxide A mixture of boron trifluoroetherate (0.01ml; 0.77mmol) and glacial acetic acid (0.16ml; 2.80mmol) in minimum chloroform (2ml) was stirred and refluxed under nitrogen for 15 minutes. A mixture of dimethoxymethane (0.07ml; 0.79mmol) and (+)-(10)-mercaptoborneol (0.13g; 0.70mmol) in chloroform (3ml) was then added slowly over 15 minutes. The reaction mixture was refluxed for 30 minutes, before being allowed to cool to room temperature. The reaction mixture was then washed with water (2x10ml), brine solution (2x10ml) and 10% aqueous potassium hydroxide (2x10ml). The organic fraction was dried over potassium carbonate. The solvent was removed in vacuo, to yield a crude product which was chromatographed eluting with 85:15 petrol :ethyl acetate to produce a compound formula (C) wherein R' and R" are both hydrogen (91mg; 69%). ! H N.M.R. data: δ H (CDCl 3 ) 4.58(lH,dd), 4.67(lH,d), 3.41-3.48(lH,m) , 2.67(lH,d), 2.30-2.42(lH,m), 2.28(lH,dd), 1.91-2.13(lH,m) , 1.38-1.62(2H,m) , 0.96-1.22(2H,m), 0.72-0.90(lH,m) , 0.74(6H,s) ppm. A solution of phenyldiazomethane (0.4δmmol in 6ml of t-butylmethyl ether was added to a solution of a compound of formula (C) wherein R' and R" are both hydrogen (90mg; 0.4δmmol), rhodium (II) acetate (2mg; 0.004δmmol) and benzaldehyde (46μl; 0.4δmmol) in dichloromethane (2ml). Upon completion of the addition, the solvent was removed in vacuo and the residue chromatographed using silica gel and elating with dichloromethane: petrol 40:60 to give the title compound (4mg, δ%, 71%ee) . EXAMPLE 50 2.3-Diphenyl-l-(4-methylphenv1sulphonyl)aziridine To a stirred solution of dimethylsulphide (7μl, 0.lmmol), rhodium (II) acetate (2mg, O.OOδmmol) and N-benzylidene-toluene-β-sulphonamide (131mg, O.δmmol; J.C.S. Perkin I (1981) 2435-2442) in dichloromethane (2ml) was added phenyldiazomethane (prepared as in Example 36; 8.11ml of a 0.074M solution in i-butylmethylether) over a period of 12 hours. Upon completion of the addition, the solvent was removed in vacuo and the residue chromatographed using silica gel eluting with 15:85 ethyl acetate:petrol to give the title compound as a 3:1 mixture of trans:cis isomers (144mg, 82%). EXAMPLE 51 2-(4-Nitrophenyl)-3-phenv1-l-(4-methylphenylsulphonyl)aziridine To a stirred solution of dimethylsulphide (δμl , 0.07mmol), rhodium (II) acetate (2mg, O.OOδmmol) and N-(4-nitrobenzylidene)toluene-p_-sulphon- amide (102mg, 0.33mmol; J.C.S. Perkin I (1981) 243δ-2442) in dichloro¬ methane (2ml) was added phenyldiazomethane (prepared as in Example 36; 8.11ml of a 0.074M solution in t-butylmethylether) over a period of 12 hours. Upon completion of the addition the solvent was removed in vacuo and the residue was chromatographed using silica gel elating with 15:85 ethyl acetate:petrol to give the title compound as a mixture of trans and cis isomers. Trans isomer (48mg, 37%) δ H (CDCl 3 ) 8.10-8.19(2H,m) , 7.δ3-7.64(4H,m), 6.95-7.41(7H,m) , 4.27(lH,d,J=6 Hz), 4.16(lH,d,J=6 Hz), 2.36(3H,s)ppm. Cis isomer (9mg; 7%) δ H (CDCl 3 ) 8.23-8.33(2H,m); 7.1δ-7.60(llH,m), 4.13(lH,d,J=2Hz) 3.87(lH,d,J=2Hz) 1.68(3H,s)ppm. EXAMPLE 52 trans-2-(4-Methoχyphenyl)-3-phenyl-l-(4-methylphenylsulphonyl)aziridine 4-Methoxybenzaldehyde (1.22ml, lOmmol) and β-toluenesulphonamide (1.71g, lOmmol) were refluxed in toluene (70ml) for 5 minutes using a Dean and Stark apparatus. Reflux was maintained while BF 3 (C 2 H,-) 2 0(0.0δml, 0.4mmol) was added via a syringe. The reaction mixture was maintained at reflux for 12 hours before being allowed to cool to room temperature whereby the title compound precipitated from the toluene. Filtration followed by recrystallisation from dichloromethane-petrol yielded M-(4-methoxybenzylidene)-toluene-o_-sulphonamide as a yellow solid (0.478g; 17%) m.p. 127°C. To a stirred solution of dimethylsulphide (7μl , 0.1 mmol), rhodium (II) acetate (2mg, O.OOδ rrrmol) and Jfi-(4-methoxybenzylidene)toluene- -p_-sulphonamide (144mg, O.δ mmol) in dichloromethane (2ml) was added phenyldiazomethane (prepared as in Example 36; 8.96ml of a 0.067M solution in t-butylmethylether) over a period of 12 hours. Upon completion of the addition the solvent was removed in vacuo and the residue was chromatographed using silica gel eluting with lδ:8δ ethyl acetate:petrol to give the title compound (96mg, δl%) . δ H (CDCl 3 ) 7.62(2H), 6.7δ-7.4δ(llH,m) , 4.3δ(lH,d,J=6Hz), 4.18(lH,d,J=6Hz) , 3.62(3H,s), 2.3δ(3H,s)ppm. EXAMPLE 53 trans-2-(N.N-Diethylacetamido)-3-phenyl-l-(4-methylphenylsulphonyl)- aziridine. To a stirred solution of dimethylsulphide (0.014ml, 0.2mmol), rhodium (II) acetate (4mg, O.Olmmol) and H-benzylidenetoluene-o_-sulphonamide (260mg, 1.0 mmol) in dichloromethane (2ml) was added a solution of fi.M-diethyldiazoacetamide (prepared by using ϋ,N-diethylacetoacetamide in place of 1 butylacetoacetate in a preparation described in Org. Synth. Collective Volume V page 179; 141mg, 1.0 mmol, in 6ml t-butylmethyl ether) over a period of 24 hours via a syringe pump. Upon completion of the addition, the solvent was removed in vacuo to yield the title compound (56mg; lδ%) . δ H (CDCl 3 ) 7.10-7.91(9H,m) , 4.40(lH,d,J=4Hz) , 3.10-4.10(4H,m) , 3.40(lH,d,J=4Hz), 2.30(3H,s), l.lδ(6H,m) ppm. EXAMPLE δ4 trans-2-(N.N-Diethylacetamido)-3-(4-chlorophenyl)oxirane To a stirred solution of tetrahydrothiophene (6μl , 0.lmmol), rhodium (II) acetate (2mg, O.OOδmmol) and β-chlorobenzaldehyde (71mg, O.δmmol) in dichloromethane (2ml) was added a solution of ϋ.M-diethyldiazoacetamide (see Example δ3 for praparation, 70mg, O.δmmol, in 6ml i-butylmethyl ether) over a period of 24 hours via a syringe pump at 60°C. Upon completion of the addition, the solvent was removed in vacuo and the residue chromatographed using silica gel eluting with petrol :ethyl acetate 1:1 to yield the title compound (25mg, 20%). δ H (CDCl 3 ) 1.14-1.30(6H,m), 3.30-3.52(4H,m), 3.53(lH,d,J=2Hz) , 4.07(lH,d,J=2Hz) , 7.22-7.40(4H,m)ppm. EXAMPLE δδ Styrene oxide To a solution of diethyl zinc (18ml of 1.1M solution in toluene, 20mmol) in 1,2-dichloroethane (60ml) was added chloroiododomethane (2.18ml, 30πrmol) at -lδ°C and the reaction mixture was stirred for lδ minutes. Tetrahydrothiophene (2.40ml, 30mmol) was added at -lδ°C and the mixture was stirred for 2δ minutes. During this time the temperature was allowed to rise to 19°C. Benzaldehyde (2.12ml, 20mmol) was added and the reaction mixture was stirred until it reached room temperature. The reaction mixture was stirred at room temperature for 1 hour after which it was diluted with dichloromethane (20ml) and washed with a saturated solution of NH-C1 (3xδml). The organic layer was dried over MgS0 4 - The resulting solution was analysed by gas chro atography and the title compound was found to be present. EXAMPLE 56 2-Phenyl-3-vinv1oxirane To a stirred solution of dimethyl sulfide (l.Ommol), rhodium (II) acetate (O.Olmmol) and acrolein (lmmol) in dichloromethane (4ml) was added a solution of phenyldiazomethane (lmmol in 6ml of tert-butvl methyl ether, prepared as in Example 1) at room temperature over a period of 3 hours. After the addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica (eluant dichloromethanre:petrol; 40:60) to give the title compound in 54% yield. δ H (CDC1 3 ); 7.20(5H,m), δ.7δ(lH,m), δ.δ(lH,dd,J=2,J=12Hz), 4.8δ(lH,dd,J=2,J=12Hz) , 3.δδ(lH,d,J=2Hz) , 3.30(lH,dd,J=2,J=9Hz)ppm. EXAMPLE δ7 2.3-Di henyl-1-diphenylphosphinylaziridine Diphenylphosphiπic acid (10.Og, 4δ.9mmol) was heated gently at reflux in dry tolune (7δml) with freshly distilled thionyl chloride (6.70ml; 91.8mmol) for two hours, according to the method of Jennings (Jennings, W.B; Lovely, CJ; Tetrahedron, (1991) 47 5561) . The solvent was then removed in vacuo to give crude diphenyl-H-phenylmethylene phosphinic chloride (9.0g; 83%) which was used without further purification. £ ι £-diphenylphosphinic amide was prepared following the method of Jennings (ibid) by adding crude diphenyl-H-phenylmethylene phosphinic chloride (9.0g; 38.05mmol, prepared above) in dry dichloromethane (20ml) to a stirred mixture of saturated ethanolic ammonia solution (100ml) and dry dichloromethane (40ml) cooled using an ice/salt bath. Subsequent work-up gave £,£-diphenylphosphinic amide (7.2g; 87%). £,£-diphenyl-N-phenylmethylene phosphinic amide was prepared following the method of Jennings (ibid) by adding titanium tetrachloride (63δml; δ.78mmol) in dry dichloromethane (10ml) to a stirred solution of benzaldehyde (1.17ml; ll.δ9mmol), £,£-diphenylphosphinic amide (2.52g; ll.δ9mmol) and anhydrous triethylamine (4.84ml; 34.78mmol) in dry dichloromethane (δOml) at 0°C. Upon completion of the addition, the stirring was maintained at 0 o C for a further 4 hours. Subsequent work-up gave £,£-diphenyl-N-phenylmethylene phosphinic amide (1.4g; 40%). To a sitrred solutuion of dimethyl sulfide (12μl, 0.16mmol), rhodium (II) acetate (3.δmg; 0.0079mmol) and £,£-diphenyl-N-phenylmethylene phosphinic amide (241mg; 0.79mmol) in dichloromethane (2ml), was added a solution of phenyldiazomethane (8.4ml of 0.094M solution in tert-butvl methyl ether), at room temperature over 14 hours via a syringe pump. Upon completion of the addition, the solvent was removed in vacuo. Chromatography using 1:1 ethyl acetate:petrol gave a mixture (6:1) of trans- and cis- 2,3-diphenyl-l-diphenylphosphinyl aziridine (20δmg, 66%). δ H (CDCl 3 ): 4.05(1.72H,d, J=16Hz) , 4.16(0.28H,d,J=18Hz) , 7.10-7.4δ(16H,m) , 7.50-7.65(1.72H,m), 7.75-7.85(1.72H,m) , 7.90-8.0δ(0.δ6H,m)ppm. EXAMPLE 58 2-(3-Chlorophenyl)-3-phenv1 oxirane To a mixture of sodium methoxide solution (30% in methanol, 0.360g), - 26 - methanol (1.33g) and tert-butvlmethvlether (δml) was added ϋ-nitroso-N-(3-chlorobenzyl)-p_-toluenesulphonamide (0.δ4g) over lδ minutes. The resulting mixture was stirred at room temperature for 30 minutes and then refluxed for lδ minutes. Water (4ml) was added to the mixture once it had cooled to room temperature. The organic layer was washed with further quantities of water (2x4ml) and then dried over anhydrous sodium sulphate. After decanting the organic solution from the sodium sulphate, the sodium sulphate was washed with tert-butvlmethvlether (2xlml) and these washings were combined with the decanted organic solution of 3-chlorophenyldiazomethane. To a slurry of rhodium (II) acetate (O.OOlg) and dichloromethane (4ml) were added benzaldehyde (0.02δml) and dimethylsulphide (0.009ml). The solution of 3-chlorophenyldiazomethane (produced above) was added to this mixture over 24 hours. The solvent was removed in vacuo and the residue chromatographed on silica (Merck grade 60, 230-400 mesh) eluting with dichloromethane:hexane 2:3 to give the title compound as a colourless oil (0.030δg, δ3% yield) δ H (CDCl 3 ): 7.δδ(8H); 7.4δ(lH), 4.0(2H)ppm. EXAMPLE 69 Stilbene oxide To a mixture of rhodium (II) acetate (0.0021g), dichloromethane (4ml) and benzaldehyde (0.051ml) was added l-methoxy-4-methylthiobenzene (0.0036ml). To this mixture was added, with stirring, a solution of phenyldiazomethane (lmmol in tert-butylmethyl ether (8ml)) over 19 hours. The reaction mixture was stirred or a further 5 hours after which the mixture was allowed to stand at room temperature for 2 days. The solvent was removed in vacuo and the residue chromatographed on silica using dichloromethane:hexane 2:3 as eluant. The title compound was obtained as a colourless oil (0.0713g, 22.6% yield). EXAMPLE 60 2-(4-Chlorophenyl)-3-phenyloxirane Phenyldiazomethane (1 mmol in 6ml of tert-butvl methyl ether, as prepared in Example 1), was added to a stirred solution of dimethylsulphide (l.Ommol), rhodium (II) trifluoroacetamide (O.Olmmol) and p-chlorobenzaldehyde (lmmol) in dichloromethane (4ml) at room temperature over a period of 3 hours. After the addition was completed the solvent was removed in vacuo and the residue was chromatographed over silica (eluent dichloromethane:petrol (2:3)] to give the title compound in 83% yield. CHEMICAL FORMULAE (AS IN DESCRIPTION) CHEMICAL FORMULAE (AS IN DESCRIPTION) (H) (F) Scheme 1 Scheme 2 X"X'

Claims: Cl aims 1. A process for the preparation of an oxirane, aziridine or cyclopropane of formula (I) : wherein, X is oxygen, NR 4 or CHR5; R1 is hydrogen, alkyl, aryl, 2 heteroaromatic, heterocyclic or cycloalkyi; R is hydrogen, alkyl, aryl,heteroaromatic, C0«R , CHR NHR , heterocyclic or cycloalkyi; or 1 2 3 R and R join together to form a cycloalkyi ring; R is hydrogen, o Q o n alkyl, aryl, heteroaromatic, C0,R , R -,Sn, CONR R or trimethylsilyl; 4 5 R and R are, independently, alkyl, cycloalkyi, aryl, heteroaromatic, S0 9 R 8 , S0-,R 8 , COR 8 , C0 R 8 , C0NR 8 R 9 or CN, or R 4 can also be 8 9 13 P(0)(aryl) 9 ; R and R are independently alkyl, aryl or arylalkyl; R and R 14 are independently hydrogen, alkyl or aryl; the process comprising reacting a mixture of a compound of formula (II): 1 2 wherein R , R and X are as defined above, and a sulphide of formula SR R , wherein R and R are independently alkyl, aryl or heteroaromatic, or R and R join together to form a cycloalkyi ring which optionally includes an additional heteroatom, with either (i) a metallocarbon obtainable by reacting an alkylmetal with a methane derivative of formula CHR X'X", wherein R is as defined above, and X 1 and X" are independently, a leaving group, or (ii) a metallocarbon obtainable by reacting a compound of formula (III): 2 (wherein R may not be hydrogen) with a suitable organometallic or inorganic reagent. 2. A process as claimed in claim 1 wherein R is hydrogen. 3. A process as claimed in claim 1 or 2 comprising: a) reacting a metallocarbon (obtainable by reacting an alkyl metal with a methane derivative of formula CHR 3 X'X") with a sulphide of formula SR 6 R 7 ; and b) reacting the product of (a) with a compound of formula (II). 4. A process as claimed in claim 1, 2 or 3 comprising: a) reacting an alkyl metal with a methane derivative of formula CHR 3 X'X"; b) reacting the product of (a) with a sulphide of formula SR 6 R 7 ; and c) reacting the product of (b) with a compound of formula (II). 5. A process as claimed in claim 1 or 2 comprising: a) reacting a metallocarbon (obtainable by reacting a 3 compound of formula (III) (wherein R is not hydrogen) with a suitable organometallic or inorganic reagent) with a sulphide of formula SR R ; and, b) reacting the product of (a) with a compound of formula (II). 6. A process as claimed in claim 1, 2 or 5 comprising: a) reacting a compound of formula (III) (wherein R is not hydrogen) with a suitable organometallic or inorganic reagent; b) reacting the product of (a) with a sulphide of formula SR 6 R 7 ; and, c) reacting the product of (b) with a compound of formula (II). 7. A process as claimed in claim 1, 2, 5 or 6 comprising adding 3 a compound of formula (III) (wherein R is as defined in claim 1 but is not hydrogen) to a mixture of a sulphide of formula SR R , a compound of formula (II) and an organometallic or inorganic reagent. A process as claimed in claim 7 wherein the addition is over a period of 2 to 36 hours. A process as claimed in claim 7 or 8 wherein the sulphide is present in a less than stoichiometric amount.

Inventors: ABDEL-RAHMAN HESHAM NIMER HASA, AGGARWAL VARINDER KUMAR, LEE HEE YOON, ABDEL-RAHMAN, HESHAM, NIMER, HASAN, AGGARWAL, VARINDER, KUMAR, LEE, HEE, YOON
Applicants: ABDEL RAHMAN HESHAM NIMER HASA, AGGARWAL VARINDER KUMAR, LEE HEE YOON, ZENECA LTD, ABDEL-RAHMAN, HESHAM, NIMER, HASAN, AGGARWAL, VARINDER, KUMAR, LEE, HEE, YOON, ZENECA LIMITED
Application year: 1994
Main classification: C07D203
IPC codes: C07B37, C07B41, C07B43, C07C2, C07C13, C07C45, C07C49, C07C69, C07C211, C07C303, C07C315, C07D203, C07D301, C07D303, C07D407, C07F9